ESS - MPPT not reducing demand on batteries

I have setup an ESS system with a battery and MPPT controller. Grid is turned off.

If I turn off the MPPT, the output of the battery does not change. Surely it should be discharging at a lesser ampage when the MPPT is producing power?

Thanks

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Matthias Lange - DE ♦ commented · Sep 06, 2021 at 11:49 AM

What batteries do you have?

What other components are in the system?

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deangi Matthias Lange - DE ♦ commented · Sep 07, 2021 at 05:20 PM

Currently, for testing, it is a 100ah AGM. Waiting for Lithium to turn up. Thanks.

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deangi Matthias Lange - DE ♦ commented · Sep 07, 2021 at 05:33 PM

Sorry, further detail:

Multiplus 12/1600

100ah AGM

75/15 MPPT with 120W input

Cerbo OS on PI

Thats all. It is a trial system before designing a much larger one.

Thanks

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klim8skeptic ♦ commented · Sep 06, 2021 at 12:21 PM

Is the mppt on the battery side of the shunt?

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deangi klim8skeptic ♦ commented · Sep 07, 2021 at 05:20 PM

No shunt in system at the moment. I understood this was not a requirement. Am I incorrect?

Thanks

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basil katakuzinos deangi commented · Sep 12, 2021 at 05:01 PM

From my understanding many of those values will be "Calculated" and not exact, especially without a shunt or BMS communicating with your GX device or inverter. If you can see watts coming into your system from the MPPT, I would not be too worried.

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